CEF调用C#

//在加载页面之前植入
browser.JavascriptObjectRepository.Register("googleBrower", new JsExtention(), isAsync: false, options: BindingOptions.DefaultBinder);

        public class JsExtention
        {
            public string MessageText = "111111";
            public void showTest()
            {
                MessageBox.Show("this in C#.\n\r" + MessageText);
            }
        }

js代码
 googleBrower.showTest();